You should always position HUD/GUI/etc in relative terms (for e.g. relative to the edge of the screen) to make your game aspect-ratio-independent.

As for different sizes, this is a design issue. Non-artists and certain programmers might just want to scale the game's assets, but this is a poor design choice.

"It’s simply not possible to create excellent, detailed icons which can be arbitrarily scaled to very small dimensions while preserving clarity. Small icons are caricatures: they exaggerate some features, drop others, and align shapes to a sharp grid."All the sizes of iOS app icons

Simply scaling down:

Better practice, re-designing the assets for different target sizes:

Another thing to consider: do you want to support full-screen on desktop?- If you don't care, then just design your game with a fixed size. The differences between Android/desktop will be minimal.- If you do want full-screen support, you'll likely need a significant redesign of your game/assets/HUD/layout/etc.

java-gaming.org is not responsible for the content posted by its members, including references to external websites,
and other references that may or may not have a relation with our primarily
gaming and game production oriented community.
inquiries and complaints can be sent via email to the info‑account of the
company managing the website of java‑gaming.org